In fiber optic communications, Wavelength Division Multiplexing (WDM) is a technology which multiplexes a number of optical carrier signals received from light sources operating at different wavelengths onto a single optical fiber where the optical carrier signals are transported over long distance. At a drop location, the WDM also demultiplexes optical signals that are carried on a single optical fiber onto a number of optical carrier signals. A WDM system may have an optical add drop multiplexer (OADM) that does both multiplexing and demultiplexing simultaneously. The OADM typically includes an optical fabric such as a Wavelength Selective Switch (WSS) or Multicast Switch (MCS) device to make optical connections that enable light signals to flow across the optical fabric.
A process of setting an optical connection in the optical fabric may involve configuring a pass-band of an optical channel in the optical fabric followed by a gradual ramp process where the optical connection (e.g. the light flow across the optical fabric) is slowly brought up. This may involve a step wise power control process through attenuation control so that light coming out from the optical fabric is gradually launched on to the line fiber. However, once the pass band of the optical channel in the optical fabric is configured, the status of the pass-band may dynamically change depending on fault conditions, equipment conditions, or facility lock conditions. Moreover, there may be a high latency between the time of service provisioning by a network operator and the time of actual provisioning in an optical fabric because each optical connection in network elements is brought up in a serialized manner from the upstream to the downstream (i.e. an automatic link turn-up mechanism). Thus, it would be desirable to have a method and apparatus that provides signaling defects associated with the phased ramp process of the optical fabric to ensure the fault, equipment, and facility lock conditions to be appropriately handled in the optical communication network.